pvjc20/du1/program.c

#include <stdio.h>

int main(){
    int c = 0;
    while(1){
        char ch;
        int num = 'a' - 'A';
        scanf("%c", &ch);
        if(ch == 'q' || ch == -1){
            break;
        }
        c++;
        if(ch <= 'A' && ch >= 'Z'){
            ch += num;
            c--;
        }
        else if(ch >= 'a' && ch <= 'z'){
            ch -= num;
            c--;
        }
        printf("%c", ch);
    }
    printf("%d\n", c);
}